List of nearest stars and brown dwarfs

There are 52 stellar systems beyond our own Solar system that currently lie within 5.0 parsecs (16.3 light-years) of the Sun. These systems contain a total of 63 stars, of which 50 are red dwarfs, by far the most common type of star in the Milky Way. Much more massive stars, such as our own, make up the remaining 13. In addition to these "true" stars, there are 11 brown dwarfs (objects not quite massive enough to fuse hydrogen), and 4 white dwarfs (extremely dense objects that remain after stars such as our Sun exhaust all fusable hydrogen in their core and slowly shed their outer layers while only the collapsed core remains). Despite the relative proximity of these objects to Earth, only nine (not including the Sun) are brighter than 6.5 apparent magnitude, the dimmest magnitude visible to the naked eye from Earth.[1] All of these objects are located in the Local Bubble, a region within the Orion–Cygnus Arm of the Milky Way.

Based on results from the Gaia telescope's second data release from April 2018, an estimated 694 stars will possibly approach the Solar system to less than 5.0 parsecs (16 light-years) over the next 15 million years. Of these, 26 have a good probability to come within 1.0 parsec (3.3 light-years) and another 7 within 0.5 parsecs (1.6 light-years).[2] This number is likely much higher, due to the sheer number of stars needed to be surveyed; a star approaching the Solar System 10 million years ago, moving at a typical Sun-relative 20–200 kilometers per second, would be 600–6,000 light years from the Sun at present day, with millions of stars closer to the Sun. The closest encounter to the Sun so far predicted is the low-mass orange dwarf star Gliese 710 / HIP 89825 with roughly 60% the mass of the Sun.[3] It is currently predicted to pass 19,300 ± 3,200 astronomical units (0.305 ± 0.051 light-years) from the Sun in 7000128000000000000♠1.280+0.041−0.039 million years from the present, close enough to significantly disturb our Solar System's Oort cloud.[2][3]

The easiest way to determine stellar distance to the Sun for objects at these distances is parallax, which measures how much stars appear to move against background objects over the course of Earth's orbit around the Sun. As a parsec (parallax-second) is defined by the distance of an object that would appear to move exactly one second of arc against background objects, stars less than 5 parsecs away will have measured parallaxes of over 0.2 arcseconds, or 200 milliarcseconds. Determining past and future positions relies on accurate astrometric measurements of their parallax and total proper motions (how far they move across the sky due to their actual velocity relative to the Sun), along with spectroscopically determined radial velocities (their speed directly towards or away from us, which combined with proper motion defines their true movement through the sky relative to the Sun). Both of these measurements are subject to increasing and significant errors over very long time spans, especially over the several thousand-year time spans it takes for stars to noticeably move relative to each other.[4]

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The classes of the stars and brown dwarfs are shown in the color of their spectral types (these colors are derived from conventional names for the spectral types and do not represent the star's observed color). Many brown dwarfs are not listed by visual magnitude but are listed by near-infrared J bandapparent magnitude due to how dim (and often invisible) they are in visible colors. Some of the parallax and distance results are preliminary measurements.[5]

This map shows all of the star systems within 14 light-years of the Sun (shown as Sol), except for brown dwarfs discovered after 2009. Double and triple stars are shown "stacked", but the true location is the star closest to the central plane. Color corresponds to the table above.

This is a 3D map of the nearest stars using the coordinates listed above. The stars in the front have a right ascension of 18h. An animated version is available here. 3D red green glasses are recommended to view this image correctly.

The locations of the four star systems closest to the Sun. Two, a brown dwarf and a free planet were found by the WISE satellite. The year when the distance to each system was determined is listed after the system's name.

Over long periods of time, the slow independent motion of stars change in both relative position and in their distance from the observer. This can cause other currently distant stars to fall within a stated range, which may be readily calculated and predicted using accurate astrometric measurements of parallax and total proper motions, along with spectroscopically determined radial velocities. Although predictions can be extrapolated back into the past or forward into the future, they are subject to increasing significant cumulative errors over very long periods.[4] Inaccuracies of these measured parameters make determining the true minimum distances of any encountering stars or brown dwarfs fairly difficult.[51]

One of the first stars known to approach the Sun particularly close is Gliese 710. The star, whose mass is roughly half that of the Sun, is currently 62 light-years from the Solar System. It was first noticed in 1999 using data from the Hipparcos satellite, and was estimated to pass less than 1.3 light-years (0.40 pc) from the Sun in 1.4 million years.[52] With the release of Gaia's observations of the star, it has since been refined to a much closer 0.178 light-years (0.055 pc), close enough to significantly disturb objects in the Oort cloud, which extends out to 1.2 light-years (0.37 pc) from the Sun.[53]

The second closest object known to approach the Sun was only discovered in 2018 after Gaia's second data release, known as 2MASS J0610-4246. Its approach has not been fully described due to it being a distant binary star with a red dwarf, but almost certainly passed less than 1 light year from the Solar System roughly 1.16 million years ago.

Distances of the nearest stars from 20,000 years ago until 80,000 years in the future

Known stars that have passed or will pass within 5 light-years of the Sun within ±3 million years[54][55]